1. Field of the Invention
The present invention relates to an impact structure for an impact power tool, in which an operation body can be rotated by imparting an impact force to the operation body by means of a hammer body.
2. Description of the Related Art
There has been known an impact power tool as a power tool for fastening or unfastening a bolt. In such an impact power tool, an operation body is rotated by intermittently hitting a pawl member of a hammer body, which is rotated by means of a driving actuator such as an electric motor, against a wing member of the operation body in the rotational direction of the hammer body.
The conventional impact power tool has at least two pawl members and at least two wing members, which are disposed at proper positions so as to cause the simultaneous impact contact of the pawl members with the wing members, as described for example in Japanese Utility Model Provisional Publication No. H1-170,570). The impact contacting areas of the pawl member and the wing member are formed into a flat surface so that they are brought into surface contact with each other.
However, in the conventional impact power tool, in which the impact contacting areas of the pawl member and the wing member are formed into the flat surface so that they are brought into surface contact with each other for imparting impact force to the operation body, the transmission of the impact force is conducted through the entirety of the impact contacting area of the pawl member. As a result, the dispersion of force easily occurs due to the flat surface of the pawl member, thus making it impossible to transmit the sufficient driving torque to the operation body. Using a large-sized hammer body can solve the problem. In this case, it is however necessary to make the operation body also in a large size in order to ensure its strength. Accordingly, the product as the impact power tool becomes large and heavy, thus degrading its maneuverability.
It is very hard to cause the simultaneous impact contact of all the pawl and wing members. When there is a small error in production, all the pawl members cannot simultaneously be brought into contact with the corresponding wing members, making a noise.